The Carlyle Group Inc. (NasdaqGS:CG) is in advanced talks to acquire ManTech International Corporation (NasdaqGS:MANT) according to people familiar with the matter. A deal could be announced as soon as this week, said the people, who asked not to be identified because the information is private. The transaction values ManTech at about $4 billion, the people said.

An agreement isn't finalized and talks could still fall apart. Representatives for ManTech and Carlyle couldn't be reached for comment.